How long can nosocomial pathogens survive on textiles? A systematic review

Aims: Healthcare-associated infections linked to contaminated textiles are rare but underline their potential role as a source for transmission. The aim of the review was to summarize the experimental evidence on the survival and persistence of the different types of nosocomial pathogens on textiles. Methods: A literature search was performed on MedLine. Original data on the survival of bacteria, mycobacteria, and fungi and persistence of viruses on textiles were evaluated. Results: The survival of bacteria at room temperature was the longest on polyester (up to 206 days), whereas it was up to 90 days for some species on cotton and mixed fibers. Only low inocula of 100 CFU were found on all types of textiles with a short survival time of ≤3 days. Most bacterial species survived better at elevated air humidity. The infectivity of viruses on textiles is lost much faster at room temperature, typically within 2–4 weeks. Conclusions: Contaminated textiles or fabrics may be a source of transmission for weeks. The presence of pathogens on the coats of healthcare workers is associated with the presence of pathogens on their hands, demonstrating the relevance of textile contamination in patient care.


Introduction
Healthcare-associated infections linked to contaminated textiles are rare, but play a role as a potential source of transmission. One example is the spread of group A streptococcus infections. An outbreak on a geriatric medical ward was explained by the presence of one healthcare worker (HCW) on the ward who was perineal carrier. Contamination of a fabric-upholstered chair used by the HCW in an office adjacent to the ward was also detected and was suspected to have enhanced the transmission to other HCWs [1]. Another example is an outbreak of meropenem-resistent A. baumannii on an intensive care unit. The major source appeared to be the curtains surrounding the patient' beds [2]. Feather pillows have been described as an unexpected source of Acinetobacter spp., potentially causing outbreaks [3]. Outbreaks caused by bacterial spores on linen have also been reported, e.g., resulting in bacteraemia [4], [5]. Work garments have also been described to be contaminated with various types of microorganisms. The cuffs of longsleeved coats frequently contact patients or environmental surfaces [6]. Soiled linen was also described as the source of tinea corporis infections in two HCWs who had only indirect contact to a patient infected with T. tonsurans [7]. The survival of nosocomial pathogens on inanimate surfaces has been well described [8]. But the persistence of pathogens on different types of textiles has not been reviewed. The purpose of this review was therefore to summarize the experimental evidence on the survival and persistence of the different types of nosocomial pathogens on textiles.  (32 hits), and silk mycobacterium survival (0 hits). Publications were included and results were extracted from them when they provided original data on the survival or duration of persistence of bacteria, mycobacteria, fungi or viruses on textiles. Articles were excluded when they did not provide any original data on survival or persistence. Reviews were also excluded, but screened for any information within the scope of the review.

Bacteria Cotton
On cotton, many bacterial species are able to survive at room temperature for long periods of time, such as  (Table 1).

Synthetic fibers
On synthetic fibers such as polyester, the survival times of high inocula at room temperature ranged from up to

Mixed and other fibers
High inocula applied to mixed and other fibers were able to survive at room temperature for up to 90 d

Fungi
Most fungal species applied as high inocula were able to survive at room temperature on various types of fibers for 30 d or more (A. fumigatus, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis, C. neoformans), 21 d (G. candidum), or 14 d (C. albicans). The differences between the fiber materials were variable. Four fungal species survived better on cotton or wool, three species on the blended fiber, and two on silk (Table 4).

Synthetic fibers
On synthetic fibers, some viruses kept their infectivity at room temperature for 12 d (ebolavirus), up to 7 d (influenza A virus, norovirus), or up to 3 d (calicivirus). The metapneumovirus could only persist for less than 1 d (Table 6).

Mixed and other fibers
On the different types of fibers, viruses kept their infectivity at room temperature for up to 28 d (vacciniavirus), 14 d (calicivirus, norovirus), 12 d (foot-and-mouth disease virus) and 10 d (poliovirus). The influenza A virus, however, persisted only for up to 1 h. A low temperature enabled the vacciniavirus to persist longer, whereas the foot-and-mouth disease virus lost its infectivity sooner (Table 7).

Discussion
The compilation of data shows that the survival of bacteria at room temperature was the longest on polyester (up to 206 d), whereas it was 90 d for some species on cotton and mixed fibers. Only low inocula of 100 CFU were found on all types of textiles with a short survival time of ≤3 d. Most bacterial species survived better at elevated air humidity. The infectivity of viruses on textiles is lost much faster at room temperature, typically within 2-4 w. These data show that contaminated textiles may well serve as a source of transmission, provided the inoculum is high enough. Elevated air humidity is an advantage for survival of bacteria. These data may have implications for the washing intervals of clothes worn at work. The duration of wear has an  impact on the overall microbial load. It has been shown that the bacterial contamination of nurses' coats is significantly higher after the second shift than after the first [9]. The change intervals in clinical practice may not reflect the real risk of contaminated clothes. In France, doctors changed their coats on average every 20 days [10]. Contaminated clothes may also have an impact on the contamination of the HCWs' hands and vice versa. The presence of pathogens on coats is associated with the presence of pathogens on the hands of HCWs, whence they were probably originally transferred to the coats. Nevertheless, this still suggests that a contaminated coat can serve as a reservoir for contamination of the HCWs' hands [11]. It has therefore been proposed that doctors leave their arms bare below the elbows, hang up their coat before patient contact, and launder their coat daily [12]. The impregnation of textiles with antimicrobial agents such as silver compounds, triclosan or copper has also been discussed to reduce their contamination in healthcare [13]. Copper-impregnated textiles can reduce multiresistant bacterial species within 1 h [14]. Among chronic ventilator-dependent patients, a significant reduction of healthcare infections indicators, such as antibiotic treatment initiation events, fever days and antibiotic usage, was described when the HCWs wore copper-oxide impregnated textiles instead of regular hospital textiles [15]. Copper-impregnated linens were even described to reduce healthcare-associated C. difficile infections [16]. Despite all the encouraging results, the permanent exposure of nosocomial pathogens to a biocidal agent is likely to enhance tolerance to this agent [17]. A. baumannii, for example, has been described to become resistant to copper, also by exposure to subinhibitory concentrations of copper [18]. The increased tolerance may well be explained by copper efflux systems [19]. Certain P. aeruginosa isolates have also been found to possess copper tolerance [20]. Items with permanent biocidal impregnation should therefore be regarded with great caution, because it seems to be a matter of time before nosocomial pathogens develop a tolerance to them, possibly even a cross-tolerance to other biocidal agents or antibiotics [21], [22], [23].

Conclusions
Contaminated textiles or fabrics may be a source of transmission for weeks. The presence of pathogens on the coats of healthcare workers is associated with the presence of pathogens on their hands, demonstrating the relevance of textile contamination in patient care.

Notes Competing interests
The author declares that he has no competing interests.